It has been discovered that in cvsnt, a multi-platform version of theoriginal source code versioning system CVS, an error in theauthentication code allows a malicious, unprivileged user, through theuse of a specially crafted branch name, to gain write access to anymodule or directory, including CVSROOT itself. The attacker can thenexecute arbitrary code as root by modifying or adding administrativescripts in that directory.

For the stable distribution (lenny), this problem has been fixed inversion 2.5.03.2382-3.3+lenny1.